Class _TemporaryFileWrapper

Lib/tempfile.py:487–556

Temporary file wrapper This class provides a wrapper around files opened for temporary use. In particular, it seeks to automatically remove the file when it is no longer needed.

class _TemporaryFileWrapper:
    """Temporary file wrapper

    This class provides a wrapper around files opened for
    temporary use.  In particular, it seeks to automatically
    remove the file when it is no longer needed.
    """

    def __init__(self, file, name, delete=True, delete_on_close=True):
        self.file = file
        self.name = name
        self._closer = _TemporaryFileCloser(
            file,
            name,
            delete,
            delete_on_close,
            warn_message=f"Implicitly cleaning up {self!r}",
        )

    def __repr__(self):
        file = self.__dict__['file']
        return f"<{type(self).__name__} {file=}>"

    def __getattr__(self, name):
        # Attribute lookups are delegated to the underlying file
        # and cached for non-numeric results
        # (i.e. methods are cached, closed and friends are not)
        file = self.__dict__['file']
        a = getattr(file, name)
        if hasattr(a, '__call__'):
            func = a
            @_functools.wraps(func)
            def func_wrapper(*args, **kwargs):
                return func(*args, **kwargs)
            # Avoid closing the file as long as the wrapper is alive,
            # see issue #18879.
            func_wrapper._closer = self._closer
            a = func_wrapper
        if not isinstance(a, int):
            setattr(self, name, a)
        return a

    # The underlying __enter__ method returns the wrong object
    # (self.file) so override it to return the wrapper
    def __enter__(self):
        self.file.__enter__()
        return self

    # Need to trap __exit__ as well to ensure the file gets
    # deleted when used in a with statement
    def __exit__(self, exc, value, tb):
        result = self.file.__exit__(exc, value, tb)
        self._closer.cleanup()
        return result

    def close(self):
        """
        Close the temporary file, possibly deleting it.